JPH0439479Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a valve structure for a shock absorber that allows damping forces on either the compression side or the expansion side to be easily and independently changed.

(Prior Art) A carbon type shock absorber is conventionally known in which an orifice is formed that generates a damping force by the deflection of a plate valve.

The valve structure of this buffer is shown in Figure 4.
A piston rod 101 is inserted into the cylinder 100, and a piston 102 fixed to the piston rod 101 defines the inside of the cylinder 100 into upper and lower oil chambers, and an oil passage 103 that communicates the upper and lower oil chambers is formed in the piston 102. Furthermore, a valve case 104 and a valve stopper 1 are provided on one side of the piston 102.
05, valve seat 106 and valve center 1
A plate valve 108 is provided via 07.

On the extension side where the piston rod 101 moves downward, as shown in FIG. On the compression side where the flow path 109 is formed and the piston rod 101 moves upward, the outer diameter portion of the plate valve 108 is bent downward by the pressure in the upper oil chamber, as shown in FIG.
A flow path 101 is formed between the round portion of the valve and the plate valve 108, and damping forces on the expansion side and compression side are generated in these flow paths 109 and 110.

(Problems to be Solved by the Invention) However, in the conventional valve structure described above, the damping force on the extension side and the compression side cannot be changed independently.

In other words, in order to increase the generated damping force, it is sufficient to increase the thickness of the plate valve or increase the number of plate valves.
To lower the damping force, you can do the opposite, but if you do this, the damping force will become high or low on both the extension and compression sides, so you only need to change either the extension or compression side. I can't.

In addition, if one attempts to change the damping force on either the rebound or compression side without changing the thickness of the plate valve, the piston, valve center, valve seat, etc. must be drastically changed. There's a problem.

(Means for Solving the Problems) In order to solve the above problems, the present invention creates a communication path with a predetermined cross-sectional area between the round part of the piston, the valve seat, and the valve center to dampen the valve when the plate valve closes. A notch (hereinafter referred to as "square hole") for generating force was formed facing the oil passage.

(Function) When the shock absorber is on the expansion side, either the square hole formed in the valve center and the valve seat or the square hole formed on the round part of the piston generates a damping force, and when it is on the compression side, the In other words, the other of the two square holes generates a damping force, and in order to change the generated damping force, the flow path area of the square hole may be changed.

(Example) An example of the present invention will be described below based on the accompanying drawings.

FIG. 1 is a cross-sectional view of the main part of a shock absorber to which the structure according to the present invention is applied. A piston rod 2 is inserted into the cylinder 1 from below, and the upper part of the piston rod 2 is between the small diameter part and the large diameter part. A valve case 3 is inserted into the stepped portion 2a from above, a valve stopper 4 is placed on top of this valve case 3, a valve seat 5 is placed on top of this valve stopper 4, and a valve center 6 is placed on top of this valve seat 5. Furthermore, a piston 7 is superimposed on this valve center 6, and these members are fixed to the upper small diameter portion of the piston rod 2 by a nut 8.

Further, a piston ring 9 is fitted onto the outer peripheral surface of the piston 7 and slides into contact with the inner peripheral surface of the cylinder 1, and upper and lower oil chambers S ₁ and S ₂ defined by the piston 7 are bored in the piston 7. A plate valve 11 that communicates with the oil passage 10 and is positioned on the lower surface side of the piston 7 by the valve center 6 is provided.

Further, a round portion 12 that projects downward is formed at the lower outer diameter portion of the piston 7, and this round portion 1
A square hole 13 is formed in 2. In addition, the valve seat 5 and the valve center 6 also have square holes 14.
is formed.

Next, the effects on the elongation side and compression side will be described below.

First, when the piston rod 2 moves downward on the extension side, the pressure in the lower oil chamber _S2 causes the inner diameter part of the plate valve 11 to bend upward as shown in FIG. 2, causing the plate valve 11, valve seat 5, and valve center to In addition to oil flowing through the passage 15 between the piston 7
Oil flows through the square hole 13 formed in the round part 12 of. Here, since the square hole 14 located on the inner diameter side of the plate valve 11 is integrated with the flow path 15, it does not act as a hole for generating damping force on the expansion side, but when the square hole 13 is on the expansion side Acts as a square hole for generating damping force. Furthermore, during compression when the piston rod 2 moves upward, the pressure in the upper oil chamber _S1 causes the outer diameter portion of the plate valve 11 to bend downward as shown in FIG. A flow path 16 is opened in between, and the oil in the upper oil chamber S ₁ passes through a square hole 14 formed in the valve seat 5 and the valve center 6 in addition to this flow path 16 to the lower oil chamber S _{2 .}
flows into. Here, since the square hole 13 located on the outer diameter side of the plate valve 11 is integrated with the flow path 16, it does not act as a hole for generating damping force during compression. It acts as a square hole for generating damping force.

In this way, the square hole 13 generates damping force on the extension side, and the square hole 14 generates damping force on the compression side, so by changing the flow path area of these square holes 13 and 14, damping force can be applied to the expansion side and the compression side. The damping force can be changed independently.

Although the illustrated example shows an example in which the piston rod is inserted from below, the same applies to a type in which the piston rod is inserted from above.

(Effect of the invention) As explained above, according to the invention, in a valve structure equipped with a plate valve, the inner diameter side and the outer diameter side of the plate valve act only on the expansion side and compression side of the buffer, respectively. Since the square hole is formed, the damping force on the extension side and the compression side can be changed independently, and this change can be made without making any major changes to the valve structure.

[Brief explanation of the drawing]

Figure 1 is a sectional view of the main parts of a shock absorber to which the valve structure according to the present invention is applied, Figures 2 and 3 are diagrams explaining oil flow on the expansion side and compression side, and Figure 4 is a diagram of a conventional valve. The cross-sectional views of the structure, FIGS. 5 and 6, are diagrams explaining the flow of oil through the valve structure shown in FIG. 4. In addition, in the drawing, 1 is a cylinder, 4 is a valve stopper, 5 is a valve seat, 6 is a valve center, and 7
1 is a piston, 11 is a plate valve, 12 is a round portion, and 13 and 14 are notches (square holes).

Claims (1)

[Scope of utility model registration request] A piston is slidably disposed within the cylinder to define two oil chambers within the cylinder, and the oil chambers are communicated through an oil passage formed in the piston, and a valve seat and a valve center are provided on one side of the piston. In the shock absorber, a ring-shaped plate valve is provided through the piston, and the round part on the outer periphery of the piston and the respective sides of the valve seat and the valve center are alternately opened and closed depending on the direction of movement of the piston. The round part, the valve seat, and the valve center are each formed with a notch facing the oil passage, which forms a communication passage with a predetermined cross-sectional area and generates a damping force when the plate valve is closed. The valve structure of the buffer.